With the U.S. Environmental Protection Agency noting that the system used to capture caustic seepage along the Bay Harbor shoreline has been ineffective in several areas, CMS Energy is planning some augmentation steps in the months ahead.

Based on data collected from spring through fall in 2007, EPA on-scene coordinator Brian Kelly said his agency identified three small areas in which pH levels along the shoreline commonly exceeded the acceptable range and directed CMS to make improvements.

"CMS has produced conceptual designs about what they propose to do in these three areas, and EPA and CMS have been discussing what the actual schedule would be to do that," he added.

Jackson-based CMS, a former partner in the Bay Harbor resort, is responsible for addressing seepages of cement kiln dust leachate at several points along the resort corridor. The high-pH leachate is formed when groundwater passes through underground deposits of cement kiln dust, a waste product remaining from the years when a cement plant operated in the area.

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Collection lines have been installed along several thousand feet of affected area to capture seepage before it reaches surface water.

The areas where pH levels were observed to be too high are in the vicinity of Bay Harbor's golf courses.

In one of these, known as the West CKD Area, CMS plans to remove some cement kiln dust in an effort to control pH. Noting that the dust and the fill material that would replace it would involve several thousand truckloads, CMS representatives propose to complete the work next winter in order to avoid tourist-season disruptions.

To the east, in the Pine Court area, CMS proposes to install "sipping wells" upgradient of the kiln dust this fall to restrict groundwater from interacting with the buried waste.

Further east, in the "Seep 1" area, the company has proposed the installation of a slurry wall, which would be used to help direct seepage toward collection trenches.

"We haven't fully agreed on what the date should be," Kelly said of the project timelines. "EPA would like to have it completed in this construction season so it can be monitored and corrections made."

With the need for augmentation present along about 3 percent of Bay Harbor's 2,800 feet of collection lines, CMS area manager Tim Petrosky noted that the system is 97 percent effective at controlling pH levels.

At the West CKD spot, Kelly said last year's pH measurements often were 9-10, with occasional readings in the 11 range. The Pine Court pH measurements tended to be slightly higher than 9, with readings ranging from 9-12 at Seep 1.

He added that the pH measures in those areas tended to be considerably less than the readings of 12-13 observed before the collection system was put in place.

After it's treated as needed to reduce excessive pH levels, seepage collected along the shoreline currently is trucked to either a Grand Traverse County wastewater plant or a commercial injection well near Johannesburg for disposal.

Seeking more control over the disposal process and the costs it involves, CMS is proposing to develop its own injection well near Alba to handle the seepage.

For the longer term, CMS is considering using a nearby treatment plant to process seepage from East Park before releasing it into Little Traverse Bay, and this disposal method also is under consideration for Bay Harbor. If on-site treatment is put in place, CMS would use the Alba well as a backup disposal method.

Environmental regulators have expressed some reluctance to approve the variance for mercury releases which CMS is seeking as part of its discharge permit for the East Park plant.

Surface water standards do not allow mercury to be released in concentrations greater than 1.3 parts per trillion. While CMS staff have said they plan to reduce the mercury content, they've added that proven technology wouldn't allow reductions below the 20-30 parts per trillion given the scale of their operation.